Optical character readers (OCRs), as opposed to bar code scanners, capture an image of a surface using a device such as a charged coupled array which converts the image to an electronic signal which is subsequently resolved or decoded with sophisticated software or firmware to identify characters in the captured image. Optical character readers have many applications in automated data collection systems where it is desired to rapidly and efficiently collect data in the form of characters printed on the surface of an article. One such application is collection information from mail pieces, specifically letters, flats and packages, millions of which are processed daily by postal services.
Modern, automated postal scanning systems generally consist of large, fixed pieces of capital equipment. These systems typically require that the letters and flats be properly oriented before the items are scanned for OCR readable information such as destination indicia, codes, and similar data. Typically, high speed, automated equipment is utilized to singular a batch of letters and flats into a stream, orientate the individual mail pieces for scanning and convey the mail pieces past a stationary OCR. Automated parcel scanning, on the other hand, is typically accomplished using cameras positioned to capture images of multiple sides of parcels transported past the cameras.
These automated systems may not be applicable to locations where relatively small numbers of parcels are processed. Likewise, parcels that are over weight, oversized, irregularly shaped or otherwise incompatible with automated scanning equipment, may require manual processing. In these cases, handheld optical character readers may be utilized by operators to acquire information appearing as characters on the surface of the parcel or package.
The nature of the equipment used in optical character reading, and in particular the camera and lens used to image the characters, requires that the read distance, i.e., the distance between the imaging head and the characters be consistent for accurate and successful data collection. An additional factor is the angle of incidence, the angle at which the imaging camera is positioned relative to the characters. Ideally the camera or imaging head is held perpendicular to the surface on which the characters appear to avoid angular distortion of the characters and similar problems. In the case of stationary OCR units utilized in automated systems, this does not typically present a problem insofar as articles are properly oriented prior to scanning and passed in front of an imaging head with the surface to be scanned perpendicular to, and at a controlled distance from the imaging head.
In the case of hand held units, the distance and angle requirements imposed by optical character reading equipment may be problematic. For example, when a hand-held OCR is used to read information from the surface of irregularly sized mail pieces including packages, envelopes and similar items, manual operation of a hand held OCR can require awkward, repetitive motions by the operator of the unit to successfully capture images of the area of interest, normally an address, appearing on the surface of the mail pieces. Under these conditions the speed at which information is collected as well as the accuracy of the data collected may suffer. Thus, while a hand held unit may be convenient for scanning information from articles having a wide variety of sizes and shapes, the desired level of successful character imaging is dependent upon accurate positioning of the unit by the operator.